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BACKGROUND Systematic coding systems are used to define clinically meaningful outcomes when leveraging administrative claims data for research. How and when these codes are applied within a research study can have implications for the study validity and their specificity can vary significantly depending on treatment received. SUBJECTS Data are from the Surveillance, Epidemiology, and End Results-Medicare linked dataset. STUDY DESIGN We use propensity score methods in a retrospective cohort of prostate cancer patients first examined in a recently published radiation oncology comparative effectiveness study. RESULTS With the narrowly defined outcome definition, the toxicity event outcome rate ratio was 0.88 per 100 person-years (95% confidence interval, 0.71-1.08). With the broadly defined outcome, the rate ratio was comparable, with 0.89 per 100 person-years (95% confidence interval, 0.76-1.04), although individual event rates were doubled. Some evidence of surveillance bias was suggested by a higher rate of endoscopic procedures the first year of follow-up in patients who received proton therapy compared with those receiving intensity-modulated radiation treatment (11.15 vs. 8.90, respectively). CONCLUSIONS This study demonstrates the risk of introducing bias through subjective application of procedure codes. Careful consideration is required when using procedure codes to define outcomes in administrative data.

Oxaliplatin was rapidly adopted for treatment of stage III colon cancer after FDA approval in November 2004, thus providing an opportunity to use calendar time as an instrumental variable in nonexperimental comparative effectiveness research. Assuming instrument validity, instrumental variable analyses account for unmeasured confounding and are particularly valuable in sub-populations of unresolved effectiveness, such as older individuals.We examined stage III colon cancer patients ages 65+ years initiating chemotherapy between 2003 and 2008 using US population-based cancer registry data linked with Medicare claims (N = 3,660). Risk differences for all-cause mortality were derived from Kaplan-Meier survival curves. We examined instrumental variable strength and compared risk differences with propensity score estimates.Calendar time greatly affected oxaliplatin receipt. The calendar time instrument compared patients treated from January 2003 through September 2004 (N = 1,449) with those treated from March 2005 through May 2007 (N = 1,432), resulting in 54% compliance. The 1-, 2-, and 3-year local average treatment effect of the risk differences per 100 patients in the "compliers" (95% confidence intervals) were -4.6 (-8.2, -0.44), -6.3 (-12, -0.16), and -9.2 (-15, -2.5), respectively. Corresponding propensity score-matched results were -1.9 (-4.0, 0.2), -3.4 (-6.2, -0.05), and -4.3 (-7.5, -0.96).Instrumental variable and propensity score analyses both indicate better survival among patients treated with oxaliplatin. As these results are based on different populations and assumptions, the instrumental variable analysis adds to evidence of oxaliplatin's effectiveness in older adults, who bear the greatest burden of colon cancer yet were underrepresented in clinical trials. In nonexperimental comparative effectiveness research of rapidly emerging therapies, the potential to use calendar time as an instrumental variable is worth consideration.

Provider-based research networks (PBRNs)--collaborative research partnerships between academic centers and community-based practitioners--are a promising model for accelerating the translation of research into practice; however, empirical evidence of accelerated translation is limited. Oxaliplatin in adjuvant combination chemotherapy is an innovation with clinical trial-proven survival benefit compared with prior therapies. The goal of this study is to examine the diffusion of oxaliplatin into community practice, and whether affiliation with the National Cancer Institute's (NCI's) Community Clinical Oncology Program (CCOP)--a nationwide cancer-focused PBRN--is associated with accelerated innovation adoption.This retrospective observational study used linked Surveillance, Epidemiology, and End Results-Medicare and NCI CCOP data to examine Medicare participants with stage III colon cancer initiating treatment in 2003 through 2006, the years surrounding oxaliplatin's Food and Drug Administration approval. A fixed-effects analysis examined chemotherapy use among patients treated outside academic centers at CCOP-affiliated practices compared with non-CCOP practices. Two-group modeling controlled for multiple levels of clustering, year of chemotherapy initiation, tumor characteristics, patient age, race, comorbidity, Medicaid dual-eligibility status, and education.Of 4055 community patients, 35% received 5-fluoruracil, 20% received oxaliplatin, 7% received another chemotherapy, and 38% received no chemotherapy. Twenty-five percent of CCOP patients received oxaliplatin, compared with 19% of non-CCOP patients. In multivariable analysis, CCOP exposure was associated with higher odds of receiving guideline-concordant treatment in general, and oxaliplatin specifically.These findings contribute to a growing set of evidence linking PBRNs with a greater probability of receiving treatment innovations and high-quality cancer care, with implications for clinical and research policy.

We examined whether an increased distance to a urologist is associated with a delayed diagnosis of prostate cancer among black and white patients, as manifested by higher risk disease at diagnosis.North Carolina Central Cancer Registry data were linked to Medicare claims for patients with incident prostate cancer diagnosed in 2004 to 2005. Straight-line distances were calculated from the patient home to the nearest urologist. Race stratified multivariate ordinal logistic regression was used to examine the association between distance to a urologist and prostate cancer risk group (low, intermediate, high or very high/metastasis) at diagnosis for black and white patients while accounting for age, comorbidity, marital status and diagnosis year. An overall model was then used to examine the distance × race interaction effect.Included in analysis were 1,720 white and 531 black men. In the overall cohort the high risk cancer rate increased monotonically with distance to a urologist, including 40% for 0 to 10, 45% for 11 to 20 and 57% for greater than 20 miles. Correspondingly the low risk cancer rate decreased with longer distance. On race stratified multivariate analysis longer distance was associated with higher risk prostate cancer for white and black patients (p = 0.04 and0.01, respectively) but the effect was larger in the latter group. The distance × race interaction term was significant in the overall model (p = 0.03).Longer distance to a urologist may disproportionally impact black patients. Decreasing modifiable barriers to health care access, such as distance to care, may decrease racial disparities in prostate cancer.

Prostate cancer is the leading cancer diagnosis among American men and the second most common cause of cancer-related death among this group. An estimated 218,890 new cases of prostate cancer will be diagnosed in the United States in 2007, with an estimated 27,050 deaths.1 Prostate cancer incidence and mortality rates for both blacks and whites have declined since 1991–1992; however, the incidence and mortality rates for blacks remain approximately twice as high as those for whites.2,3 Treatment options for prostate cancer vary by stage of disease, patient preference, and other comorbidities. Studies have shown treatment4,5 and treatment outcomes6,7 to differ by race. Black men are less likely to get aggressive definitive treatment compared with whites.4,5 Although survival after treatment for localized prostate cancer has been shown to be lower for blacks compared with whites, particularly after surgery,6 research to identify treatment-specific variables related to racial differences in treatment outcomes is lacking. To this end, there is a growing interest in understanding how physician and hospital characteristics affect patient care and outcomes. Hospital volume, or the number of procedures performed, is associated with more favorable outcomes for many surgical procedures, including pancreaticoduodenectomy, 8,9 esophagectomy,9 prostatectomy,10 and liver resection. 9 Previous reviews found that the majority of studies support a positive relationship between volume and outcome of initial cancer treatment for both physician and hospital.11 Other characteristics have emerged as factors related to patient outcomes. In general, studies show that physicians of black patients tend to be less well trained (eg, board certification), and have less access to important clinical resources (eg, high-quality diagnostic imaging) than physicians of white patients.12 Location, size, and type of hospital have also been associated with treatment outcomes and quality of care.13–15 These concepts and research findings suggest that, if blacks are more likely to receive care at hospitals and by physicians that differ in experience from the hospitals and physicians that whites use, this could account for some of the racial differences that are seen in treatment outcomes after prostatectomy. Previous research by Cohen and associates used the Surveillance, Epidemiology, and End-Results (SEER)-Medicare database to examine patients diagnosed with clinically localized prostate cancer from 1988 to 1996, and found racial disparities in both prostate cancer specific and all-cause recurrence-free survival, with the greatest racial difference in survival found in patients after prostatectomy.16 However, the study did not analyze whether this disparity is related to the experience level (or volume) of hospitals and surgeons who perform the prostate surgeries. This study expands upon the work of Cohen and associates to examine the relationship between physician/hospital volume and the racial disparity in survival after surgery for prostate cancer.

The National Institutes of Health is developing practice-based clinical research networks (PBRNs) to expedite the pace of scientific discovery and improve care quality. Anecdotal evidence suggests managed care penetration and provider competition negatively affect PBRN clinical research.The objective of this study is to examine the effects of environmental factors on clinical research performance in the National Cancer Institute's Community Clinical Oncology Program (CCOP).This study examined 49 CCOPs in 34 states using longitudinal (1991-2001) generalized least-squares regression including fixed effects, using secondary data from the National Cancer Institute, Group Health Association of America, InterStudy, American Hospital Association, Area Resource Files, and the Current Population Survey.Performance was measured as CCOP-level accrual in treatment trials, cancer prevention and control (CP/C) trials, and all trials combined. HMO penetration served as a proxy for managed care penetration. Competition measures included both hospital competition and physician competition.Managed care penetration was positively associated with accrual in areas of low to moderate penetration and negative in the areas of high penetration. Compared with areas with 5% penetration, areas with 15% penetration had 21% more treatment accrual and 66% more CP/C accrual. Compared with areas with 40% penetration, areas with 50% penetration had 11% lower treatment accrual and 3% lower CP/C accrual. CP/C accrual was more positively affected than treatment accrual. Greater hospital competition was associated with a decline in trial enrollment.The healthcare environment appears to have a significant effect on accrual into community-based cancer treatment and CP/C clinical trials. Findings for treatment and CP/C accrual suggest each type of accrual is distinct and requires different strategies and administrative methods.